Apropos

orType Specifier

    Compound Type Specifier Kind

    Combining.

    Compound Type Specifier Syntax
    (or {typespec}*)
    Compound Type Specifier Arguments

    typespec — a type specifier.

    Compound Type Specifier Description

    This denotes the set of all objects of the type determined by the union of the typespecs. For example, the type list by definition is the same as (or null cons). Also, the value returned by position is an object of type (or null (integer 0 *)); i.e., either nil or a non-negative integer.

    * is not permitted as an argument.

    The type specifiers (or) and nil are equivalent. The symbol or is not valid as a type specifier; and, specifically, it is not an abbreviation for (or).